1. Field of the Invention
The present invention relates generally to the field of computer systems. Specifically, the present invention relates to an implementation of a limited access device.
2. Description of the Related Art
To enhance data security in digital processing systems, closed or limited access devices to secure data access have become increasingly popular. Such closed or limited access devices, hereinafter referred to as closed devices, are particularly useful in certain military as well as government applications. A closed device is generally enclosed in a sealed chamber typically formed by metal, composite materials, or chemical coatings that are tamper resistant.
Like a typical digital processing system, a closed device generally contains a plurality of components, such as processor and memory chips. These chips may be mounted on a multi-chip module ("MCM").
However, once the MCM is sealed in the chamber, it is almost impossible to access the components except through a limited number of I/O ("input and output") ports. A MCM will not function correctly if data stored in a memory chip is corrupted. Because a sealed MCM is protected from external access, the MCM may have to be disposed of if the data stored in a memory chip of the MCM is corrupted.